Tube manifold for a steam genera-tor



March 117, 1964 o os 3,125,161

TUBE MANIFOLD FOR A STEAM GENERATOR Filed Dec. 29, 1959 5 Sheets-$heet 1 F: mi l N H I INVENTORQ NICHOLAS D. ROMANOS I Q ms ATTORNEYS March 17, 1964 N. D. ROMANOS TUBE MANIFOLD FOR A STEAM GENERATOR 3 Sheets-Sheet 2 Filed Dec. 29, 1959 INVENTOR. NICHOLAS D. ROMANOS I MUIIII L H; ,JW/

i ATTORNEYS.

March 177, 1964 N. D. ROMANOS 3,125,161

TUBE MANIFOLD FOR A STEAM GENERATOR Filed Dec. 29, 1959 3 Sheets-Sheet 3 FIG. 3.

INVENTOR;

' NICHOLAS 0. ROMANOS MMV/MA" his ATTORNEYS.

United States Patent 3,125,161 TUBE MANH GLD FUR A @TEAM GENERATGR Nicholas D. Romance, Chattanooga, Tenn, assignor to Combustion Engineering, Inc, New York, N.Y., a corpartition of Delaware Filed Dec. 29, 1959, her. No. 862,666 3 Claims. (Cl. 165-159) This invention relates to a tube manifold of the type that directs the flow of the primary fluid through a heat exchanger.

Heat exchangers are commonly employed in steam generating systems when it is desirable or necessary that heat be transferred from a primary fluid to a secondary fluid without the two fluids coming into contact. This is done by passing the fluids along opposite sides of a heating surface which provides an easy path for the flow of heat from one fluid to the other. In practice, the heating surface usually takes the form of a bank of tubes which is submerged in the secondary fluid and has the primary fluid flowing through it.

Considerable difliculties have been encountered when using conventional heat exchangers due mainly to the temperature differences which exist between the inlet and outlet conduits for the primary fluid, the secondary fluid, and the ambient atmosphere. These differences tend to set up thermal stresses in the shell that houses the heat exchanger and in the tube manifold which can cause ruptures if these parts are not built strongly enough. Other difliculties have arisen because the design of conventional tube manifolds has required unusually heavy material to Withstand the fluid pressures and pressure fluctuations. Conventional heat exchangers, therefore, are more expensive not only because very heavy material is required but also because the excessive material makes them more diflicult to construct.

Accordingly, it is the purpose of this invention to provide a heat exchanger having a tube manifold which, because of its unique design, substantially eliminates the above-described difliculties and enables the construction of a heat exchanger using relatively light gauge materials and simple construction methods.

This purpose is attained by providing a tube manifold that includes two enclosures, one of the enclosures being divided into two compartments; a plurality of tubes running from one of the compartments to the other of the compartments; the second enclosure passing through one of the compartments and having a fluid passageway leading to the other of the compartments; and an external nozzle formed on each of the enclosures.

In normal operation, the conduit carrying the relatively hot inlet primary fluid is connected to the nozzle formed on the second enclosure and the relatively cool outlet primary fluid conduit is connected to the nozzle formed on the first enclosure. By these connections, the hot inlet fluid enters the heat exchanger shell through the center of the tube manifold where it is surrounded by the relatively cool outlet fluid so that it does not at any point come close to the shell. In a preferred embodiment of the invention, the two enclosures are concentric cylinders which are advantageous because they are better able to withstand thermal and pressure stresses. Also, a cylindrical manifold can feed more tubes than a conventional flat sheet manifold.

These and other advantages will become more apparent from the following detailed description of a representative embodiment of the invention taken in conjunction with the accompanying figures of the drawings in which:

FIGURE 1 is a view in side elevation of a heat exchanger constructed in accordance with the invention;

FIGURE 2 is a view in cross section taken along the line 22 of FIGURE 1;

3,125,161 Patented Mar. 17., 1964 FIGURE 3 is a sectional view of a manifold con structed in accordance with the invention; and

FIGURE 4 is a view in cross section taken along the line 4-4 of FIGURE 3.

The heat exchanger illustrated in FIGURES 1 and 2 is characterized as a pool boiler or the reboiler type since the heating surfaces and the steam separation equipment are located within a common shell 10. The shell is substantially cylindrical and has a semi-ellipsoidal head 11 welded to each end, each head having a manway 12 formed therein. The shell is supported by two braces 13 which can be designed to rest on any suitable foundation.

A secondary fluid, or feedwater, is introduced into the shell 10 through two nozzles 14 that lead to two perforated pipes 15 which distribute the fluid along the length of the shell. The level of the secondary fluid in the shell 10 is normally suflicient to cover a plurality of tubes, to be described hereinafter, that carry the primary fluid and is indicated by a gauge glass 16 that is connected to a pair of nipples 17, FIGURE 2.

The pipes 15 are fastened to the shell 10 by a plurality of U-bolts l8, and the nozzles 14 are surrounded by thermal or insulating sleeves lfl. These sleeves are formed by spacing apart two concentric cylinders and filling this space with a suitable insulating material such as stagnant water.

When the secondary fluid is heated by the primary fluid, steam rises from its surface and passes through a steam separating and drying mechanism 20 and a plurality of steam outlet nozzles 21 to a steam-utilizing mechanism such as a turbine (not shown). The steam separating and drying mechanism includes a deflector screen 22, dryer screen 23, and a pair of plates 24 which serve to aid distribution of the steam through the screens. The center sections of the screens and the plates are partitioned off from their end sections by a pair of plates 25 (only one being shown) which separate the relatively dry steam at the center of the shell from the wetter steam near the ends.

The flow circuit of the primary fluid includes two bundles 26 and 27 of tubes that are coupled to the opposite sides of a tube manifold 28. All of the tubes have U-bends located in vertical planes, as illustrated in FIGURE 1, and have both ends connected to the mani fold 2.8. The tubes are supported at various points along their length by a plurality of panels 29, FIGURE 2, which are hung from a plurality of bars 34 and supports S l. As is shown .in FIGURE 2, the alternate vertical rows of the tubes are staggered by one-half space in order to increase their center-to-center distance. While, for ease of illustration, only a few tubes have been shown, it should be understood that the entire space within the two outlines on the panel 29, FIGURE 2, is equipped with tubes.

The tube manifold 28 is best shown in FIGURES 3 and 4 and includes a cylindrical section. 32 that is capped by a semi-ellipsoidal head 33 and a cover plate 34. The cover plate 34 is fastened to the section 32 by a plurality of studs 35, and a sea-l 36 between the section and the plate ensures a leak-proof connection. The internal surface of the manifold, well as all other parts that come in cont-act with the primary fluid, preferably have a stainless steel cladding 37, and the tubes are preferably made of stainless steel. Of course, these materials are only exemplary since the choice will depend on the nature of the primary fluid.

A divider plate 33 separates the section 32 into upper and lower compartments 39 and 4t respectively, and every tube the two bundles 25 and 27 has an end leading into each of these compartments. The divider plate 38 has an aperture formed therein which receives an internal cylinder 41. A flange 42, formed on the cylinder 3 41, has a plurality of holes formed therein, and a plur-ality of bolts 43 are threaded through the holes and into the divider plate 38. Permanently fastened to the heads of the bolts are a plurality of rods 44 :which extend nearly to the plate 34 and provide greater ease in assembling the manifold.

The nozzles 45 and 46 are formed on the cylindrical section 32, the nozzle to leading directly to the lower compartment 4%. Welded internally to the nozzle 45 is a cylindrical member 47 which, because it is spaced from the nozzle, provides a thermal sleeve of the type previously described. The internal cylinder 41 has an elbowed end as and a flange 49 termed thereon which abuts on the end of the member 47. Since the elbowed end 4:? is not fixed to the member 47, it is free to move in .a vertical direction as the cylinder 41 expands and contracts due ot thermal changes.

To prevent the fluid pressure at the nozzle 45 from displacing the elbowed end 48 toward the night, a vertical plate Si) is welded to the cylinder 41 and is bolted to a horizontal plate 51 which :abuts the inner wall of the cylindrical section 32. A pair of bolts 52 are inserted through slots in the plate 51 and two flanges 53 formed on the plate 50. By properly positioning the plate 51 between the flanges 53, the elbowed end 48 can be secured against horizontal displacement.

In operation, the relatively hot primary fluid enters the nozzle 45 and is carried to the upper compartment 39 by the internal cylinder 41. The primary fluid then enters the upper ends of the tubes in the bundles 26 and 27, flows through the tubes and out their bottom ends into the lower compartment 4t, and, finally, out of the nozzle 46. Since the conduit carrying the hot inlet primary fluid enters the shell it? through the center of the tube manifold 28, where it is surrounded by the relatively cool outlet primary fluid, it does not at any point contact the shell. Consequently, thermal gradients and stresses are substantially eliminated in both the shell and the tube manifold. This construction is especially advantageous where a high temperature difference is maintained between the primary and secondary fluids and where there are rapid fluctuations in the temperature of the primary fluid.

Another primary advantage resulting from this construction is the increased strength of the manifold due to its cylindrical shape. Still another very important advantage is that two tube bundles, one on each side of the tube manifold, can be sup-plied with primary fluid from a single manifold. This is advantageous because it requires less material and it reduces the chances of therrnal stresses damaging the shell.

While a representative embodiment of the present invention has been shown and described for purposes of illustration, it is apparent that the embodiment is susceptible of change and modification without departing from this invention in its broader aspects. Therefore, the invention described herein is not to be construed as limited to the specific embodiment described but is intended to encompass all modifications thereof coming within the scope of the following claims.

I claim:

1. A heat exchanger comprising a shell adapted, to contain a fluid, a plurality of tubes mounted in the shell, a manifold mounted in the shell to which the plurality of tubes is connected within the shell and extending to the outside of the shell, the manifold including a rigid elongated outer enclosure which is divided into two compartments and a rigid elongated inner enclosure which passes through one of the compartments and has a fluid passageway leading to the other compartment, a removable cover mounted on the end of the elongated outer enclosure outside the shell to provide longitudinal access to the interior thereof, means forming an opening in the side wall of the outer enclosure outside the shell to provide a fluid passageway to the interior of the outer enclosure, a fluid nozzle formed in the side Wall of the outer enclosure at the opening therein, and having an opening directed laterally inwardly to the interior thereof, means forming an opening in the inner enclosure directed laterally outwardly thereof adjacent to and communicating with the fluid nozzle opening, transversely extending flange means aiiixed to the means forming an opening in the inner enclosure md abutting the inner end of the nozzle so as to permit relative sliding motion of the fluid nozzle and the means forming an opening the a direction parallel to the direction of elongation of the inner and outer enclosures upon differential expansion of the inner and outer enclosures while maintaining communication between the openings therein, and means cooperating with the inner and outer enclosures to urge the flange means and the nozzle together so as to maintain sealed communication between the openings in the inner and outer enclosures while permitting relative longitudinal expansion of one of the enclosures with respect to the other.

2. A heat exchanger comprising a shell adapted to contain a fluid, a plurality of tubes mounted in the shell, a manifold mounted in the shell to which the plurality of tubes is connected within the shell and extending to the outside of the shell, the manifold including a rigid elongated outer enclosure which is divided into two compartments and a rigid elongated inner enclosure which passes through one of the compartments and has a fluid passageway leading to the other of the compartments, a removable cover mounted on the end of the elongated enclosure outside the shell to provide longitudinal access to the interior thereof, means forming an opening in the side wall of the outer enclosure to provide a fluid passageway to the interior of the outer enclosure outside the shell, a fluid nozzle aflixed to the outer enclosure at the opening in the side wall thereof including a rigid outer conduit sealed to the side wall of the outer enclosure about the opening therein and at the outside thereof and a rigid inner conduit sealed to the outer conduit at the outer end thereof and held in spaced relation to the outer conduit so as to provide an insulating space between the two which communicates with the interior of the outer enclosure and to provide a nozzle opening directed laterally inwardly to the interior thereof, means forming an opening in the inner enclosure directed laterally outwardly thereof adjacent to and communicating with the nozzle opening, transversely extending flange means affixed to the means forming an opening in the inner enclosure and abutting the inner end of the inner conduit of the nozzle so as to permit relative sliding motion of the fluid nozzle inner conduit and the means forming an opening in the inner enclosure in a direction parallel to the direction of elongation of the inner and outer enclosures upon differential expansion of the inner and outer enclosures while maintaming communication between the openings therein, and means cooperating with the inner and outer enclosures to urge the flange means and the nozzle inner conduit together so as to maintain sealed communication between the inner conduit of the nozzle and the opening in the inner enclosure while permitting relative longitudinal expansion of one of the enclosures with respect to the other.

3. A heat exchanger comprising a shell adapted to contain a fluid, a plurality of tubes mounted in the shell, a manifold mounted in the shell to which the plurality of tubes is connected within the shell and extending to the outside of the shell, the manifold including a rigid elongated outer enclosure which is divided into two compartments and a rigid elongated inner enclosure which passes through one of the compartments and has a fluid passageway leading to the other compartment, a removable cover mounted on the end of the elongated outer enclosure outside the shell to provide longitudinal access to the interior thereof, means forming an opening in the side wall of the outer enclosure outside the shell to provide a fluid passageway to the interior of the outer enclosure, a fluid nozzle formed in the side wall of the outer enclosure at the opening therein, and having an opening directed laterally inwardly to the interior thereof, means forming an opening in the inner enclosure directed laterally outwardly thereof adjacent to and communicating with the fluid nozzle opening, transversely extending flange means aifixed to the means forming an opening in the inner enclosure and abutting the inner end of the nozzle so as to permit relative sliding motion of the fluid nozzle and the means forming an opening in a direction parallel to the direction of elongation of the inner and outer enclosures upon differential expansion of the inner and outer enclosures while maintaining communication between the openings therein, and rigid plate means within the outer enclosure rigidly connected to the inner enclosure and extending to the inner surface of the side wall of the outer enclosure at a location opposite to the location of the nozzle thereon so as to abut the side wall with sufiicient pressure to urge the flange means and the nozzle together so as to maintain sealed communication between the openings in the inner and outer enclosures while permitting relative longitudinal expansion of one of the enclosures with respect to the other.

References Cited in the file of this patent UNITED STATES PATENTS 1,706,084 Steinmeyer et a1 Mar. 19, 1929 1,729,944 Hollowell Oct. 1, 1929 2,139,207 Rector Dec. 6, 1938 2,787,124 Donahue Apr. 2, 1957 2,820,437 Ilune Jan. 21, 1958 FOREIGN PATENTS 703,618 Germany Mar. 13, 1941 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0 3 l25 l6l I'll/larch 17 1964 Nicholas D, Romanos It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 3,, line l7. for "ot"read to column l line 10 for "the" second occurrence, read in column 6 list of Re ferences Cited, under the heading "FOREIGN PATENTS, add the following reference:

Signed and sealed this 7th day of July l964 (SEAL) Attest:

ERNEST W. 'SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. A HEAT EXCHANGER COMPRISING A SHELL ADAPTED, TO CONTAIN A FLUID, A PLURALITY OF TUBES MOUNTED IN THE SHELL, A MANIFOLD MOUNTED IN THE SHELL TO WHICH THE PLURALITY OF TUBES IS CONNECTED WITHIN THE SHELL AND EXTENDING TO THE OUTSIDE OF THE SHELL, THE MANIFOLD INCLUDING A RIGID ELONGATED OUTER ENCLOSURE WHICH IS DIVIDED INTO TWO COMPARTMENTS AND A RIGID ELONGATED INNER ENCLOSURE WHICH PASSES THROUGH ONE OF THE COMPARTMENTS AND HAS A FLUID PASSAGEWAY LEADING TO THE OTHER COMPARTMENT, A REMOVABLE COVER MOUNTED ON THE END OF THE ELONGATED OUTER ENCLOSURE OUTSIDE THE SHELL TO PROVIDE LONGITUDINAL ACCESS TO THE INTERIOR THEREOF, MEANS FORMING AN OPENING IN THE SIDE WALL OF THE OUTER ENCLOSURE OUTSIDE THE SHELL TO PROVIDE A FLUID PASSAGEWAY TO THE INTERIOR OF THE OUTER ENCLOSURE, A FLUID NOZZLE FORMED IN THE SIDE WALL OF THE OUTER ENCLOSURE AT THE OPENING THEREIN, AND HAVING AN OPENING DIRECTED LATERALLY INWARDLY TO THE INTERIOR THEREOF, MEANS FORMING AN OPEN- 